Endoscopic surgical procedures are routinely performed in order to accomplish various surgical tasks. In such a surgical procedure, small incisions or portals are made in the patient. An endoscope, which is a device that allows medical personnel to view the surgical site, is inserted in one of the portals. Surgical instruments used to perform other tasks are inserted into other portals. The surgeon views the surgical site through the endoscope to determine how to manipulate the surgical instruments in order to accomplish the desired procedure. An advantage of performing endoscopic surgery is that, since the portions of the body that are cut open are minimized, the portions of the body that need to heal after the surgery are likewise reduced. Moreover, during an endoscopic surgical procedure, only relatively small portions of the patient's internal organs and tissue are exposed to the open environment. This minimal opening of the patient's body lessens the extent to which the organs and tissue are open to infection.
The ability to perform endoscopic surgery is enhanced by the development of powered surgical tools especially designed to perform such procedures. Once such tool is sold by the assignee hereof under the trademark FORMULA®. This tool is in the form of a cylindrical handpiece designed to be held in the hand of the surgeon. The handpiece has a front or distal end provided with a coupling assembly for releasably holding a cutting accessory, and a motor disposed within a handpiece housing which drives the accessory. The cutting accessories, such as shavers, drills and burs, include a hub which defines the proximal end of the accessory and is appropriately configured to cooperate with the coupling assembly of the handpiece to lock the accessory thereto, an elongated and tubular housing element having a proximal end fixed to the hub, and an elongated cutting element including a drive shaft disposed within the housing element. When the accessory is attached to the handpiece, the handpiece motor couples to the drive shaft of the accessory and moves same relative to the outer housing element. The handpiece motor is selectively actuable to drive the accessory drive shaft so as to cause a desired cutting action at the distal end of the accessory. The handpiece is associated with a control unit which controls the functioning thereof, and is actuated by the user via appropriate buttons provided on the handpiece itself, at the control unit or through use of a footswitch.
In an endoscopic surgical procedure, irrigating fluid is introduced into the surgical site. This fluid serves as a transport media for removing tissue and debris from the surgical site. In order to remove the irrigating fluid and the material contained therein, the above handpiece and the various accessories which are usable therewith together define a suction conduit. A suction pump is connected to the handpiece to provide the suction force needed for drawing the fluid and material away from the surgical site. In order to control the suction flow through the accessory and the handpiece, the handpiece is typically provided with a manually operated valve which is manipulated by the surgeon to control suction of material away from the surgical site.
Mechanical cutting accessories, such as the shaver, drill and bur discussed above, are commonly used in arthroscopic procedures, and allow for the resection of hard and soft bodily tissues, for example, those found within the knee, shoulder and other joints. A bur-type cutting accessory is commonly used to resect bone or other hard tissues, and includes cutting features which when rotated serve to cut away targeted bone or hard tissue. Such cutting features may be helically-oriented or non-helically oriented. The cutting element of a bur-type cutting accessory includes a cutting head with these cutting features which are exposed through a window formed at the distal end of the outer housing element when the cutting element is located therein. In some bur-type cutting accessories, the window formed in the outer housing element opens primarily sidewardly, so that the distal end of the outer housing element covers a portion or one side of the cutting head of the bur to allow the user to better target bone or hard tissue. Alternatively, the entire cutting head geometry may project distally beyond the terminal end of the outer housing element, and this type of bur configuration is often called “unhooded”. Many bur configurations are for removal of particular bone or hard tissue types, and a variety of different bur geometries are available to specifically address the type of cutting the accessory is to carry out.
Further, in some conventional bur-type cutting accessories, the cutting element includes an elongate and hollow tubular drive shaft and the cutting head at the distal end thereof is provided as a solid member which is fixedly mounted to the distal end of the drive shaft. In order to draw suction through the cutting element in this type of accessory, the distal end of the drive shaft is provided with a suction opening which opens sidewardly outwardly and communicates with the hollow interior of the drive shaft. In operation, bone or other hard tissue removed or cut away by the cutting head is suctioned into the hollow interior of the drive shaft through the window of the outer housing element. Bur-type cutting accessories, due to their configuration, often spray surgical debris outwardly and away from the cutting features of the cutting head. Eventually, the surgical debris will be evacuated from the surgical site through the suction opening located proximally from the cutting head of the bur. However, in the interim, the debris can occlude the surgeon's field of view.
The cutting accessory disclosed in U.S. Pat. No. 5,489,291 includes an abrading element which is generally hollow and includes a plurality of helically-oriented apertures, each of which apertures is disposed between an adjacent pair of abrading ridges. These helically-oriented apertures provide a path for fluid and abraded tissue into the central bore of the tool. However, the configuration of the abrading element is primarily hollow, and the suction apertures are elongate and extend a substantial longitudinal distance along the abrading element, and such an open configuration compromises the structural integrity of the abrading element. Further, the suction apertures and the abrading ridges are formed together or at the same time, which necessarily limits the design flexibility of both the abrading ridges and the suction apertures.
While the arrangements described above serve to remove fluid and surgical debris from the surgical site, there is a continuing desire and need for improved performance in surgical tools in an effort to minimize trauma to the patient and to make the operative procedure more efficient and effective. The surgical accessory according to the invention includes a cutting element with a cutting head which incorporates one or more suction openings directly adjacent the cutting features of the cutting head. In one embodiment, the cutting head has a generally helically oriented cutting edge, and a suction opening or alternatively a plurality of openings in communication with a source of suction, are located directly adjacent the cutting edge. Another embodiment of the invention includes a cutting head with a cutting edge and a suction opening which traverses the cutting edge. A further embodiment of the invention includes a cutting head with a cutting edge which is generally straight or linear and a suction opening or a plurality of suction openings disposed directly adjacent the cutting edge.
The placement of the suction opening or openings according to the invention serves to evacuate surgical debris from the surgical site rapidly after the debris is generated and thus results in a much reduced delay between the time debris is generated and the time the debris is evacuated from the surgical site, thereby preventing or at least minimizing any occlusion of the surgeon's field of view and providing an overall clearer field of view during use of the accessory. Additionally, the size, placement and process for forming the suction openings allow for a cutting element with increased structural integrity. Further, the suction opening or openings provided in the cutting head in some embodiments are formed in a cutting step which is separate from the cutting step during which the cutting edges or features are formed. Thus, the suction opening or openings can be oriented and/or the size thereof modified without modifying the trajectory and/or configuration of the cutting features.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. The words “forwardly” and “distally” will refer to the direction toward the end of the arrangement which is closest to the patient, and the words “rearwardly” and “proximally” will refer to the direction toward the end of the arrangement which is furthest from the patient. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.